The present invention generally relates to a customer premises network, a customer premises system comprising such a network and a method for controlling the access to such a network. More specifically it relates to a home network based on ATM add/drop multiplexing and optical fibres.
In the system described in U.S. Pat. No. 5,050,164, there is described an optical customer premises network for interfacing user terminals with a broadband digital trunk and exchange network. Between the optical customer premises network and the broadband digital trunk and exchange network there is connected an optical network interface (ONI), which serves as a gateway and also provides access to certain centralised control functions. Each user terminal is associated with a respective terminal adapter, the terminal adapters being interconnected in such a way that the downstream information is dropped and the upstream information is transmitted by means of a xe2x80x9cdaisy chainxe2x80x9d, i.e. the upstream information is regenerated at each terminal adapter.
In U.S. Pat. No. 5,079,763, a divisional application of U.S. Pat. No. 5,050,164, there is described a customer premises network node access protocol for controlling the access of a plurality of terminal adapters to a bus for transmitting upstream information, the bus interconnecting the terminal adapters in a daisy chain. However, with these systems it is not possible to have a direct communication between the user terminals, since in both documents it is described that the transmissions between units of user terminals is only provided via the optical network interface (ONI).
EP-A2-0448494 relates to a DQDB network of nodes connected to each other with two data buses transmitting data in two opposite directions, upstream and downstream. Each node can transmit data to any other node of the network without passing the end nodes since each node can transmit on any of the two buses and address other nodes of the network. However, this document does not disclose interconnection of the terminal adapters in a xe2x80x9cdaisy chainxe2x80x9d. Moreover, it is not possible to add a terminal adapter without reconfiguring the network. It is an object of the present invention to overcome the disadvantages brought about with the above referenced prior art documents.
This invention is embodied in a customer premises network, a customer premises network system and a related method for controlling the access of terminal adapters to the transmission means.
The customer premises network comprises at least two terminal adapters, each being connectable to a respective user terminal, a first and second transmission means which interconnects said terminal adapters to form a daisy chain for transmitting downstream and upstream information, respectively. The terminal adapter further comprises means for filtering particular information destined for the associated user terminal from a bit stream transmitted via the first or second transmission means; and means for writing particular information from the associated user terminal into a bit stream transmitted via the first or second transmission means, wherein a protocol handler handled by means of a media access protocol is also provided.
In a more detailed embodiment of the invention, each terminal adapter, comprises a respective predetermined address value (UPI) which is related to the position of the terminal adapter in the daisy chain.
In another more detailed embodiment of the invention, said protocol handler in a first end terminal adapter generates and forwards a clock signal to the first transmission means to synchronise the terminal adapters. This is conveniently accomplished by giving the first end terminal adapter the lowest predetermined address value (UPI).
A method for controlling access of the terminal adapters to the transmission means, a protocol, which is performed by a protocol handler located in each terminal adapter, basically supports the following:
determining if an incoming request is for said specific terminal adapter and if said specific terminal adapter (100,101,102) has a request to transmit,
keeping track of the capacity of the outgoing first and second transmission means as a result of said determining steps,
transmitting said request in said request direction or an answer in said answer direction determined as a result of said keeping track step.
An advantage of the invention is that the user terminals can communicate directly with each other independently of if a network interface is connected to the customer premises network or not.
In a preferred embodiment the customer premises network uses ATM to deliver all services and the information is transmitted on large core optical fibres. The preferred embodiment has the advantages of being cable lean, insensitive to electromagnetic radiation and capable of a relatively high bus bandwidth ( greater than 100 Mb/s).